Patent Document 1 describes a technique of connecting a switch between a load resistor and a power supply (GND) and reducing current during idling by switching ON/OFF of a switch during operation and idling.
Patent Document 2 describes that squelch control is performed in a technique of retransmitting a signal using a repeater after receiving the signal using a receiving antenna in order to transmit a broadcast to an area such as building shadow where radio waves do not reach.